Although glycosaminoglycans, the carbohydrate portion of carbohydrate portion of proteoglycans, have been the subject of a number of studies of lung tissue, detailed studies of lung proteoglycan have not been made. Proteoglycans will be isolated from lung tissue by dissociative extraction and enzymatic methods designed to prevent degradation during the isolation procedure. The proteoglycans will be purified by isopycnic cesium chloride centrifugation and subsequent gel, ion exchange chromatographic, and electrophoretic methods. The molecular weights, carbohydrate chain composition, degree of sulfation, protein composition, ability to self-aggregate or aggregate in the presence of hyaluronic acid, ability to complex with soluble collagen and/or elastin, and ability to chelate divalent cations will be studied. Comparisons will be made with homologous proteoglycans from other tissues. In addition, lung parenchymal cells will be established in vitro, and proteoglycans labeled by incorporation of 35S-sulfate and/or 3H-glucosamine, will be isolated from the culture medium and the cell layer. These proteoglycans will be compared with those from lung tissue, in order to establish the validity of using isolated, cultured lung cells as models for proteoglycan biosynthesis in vivo. Other cell types and mixed cells from lung tissue will be cultured in vitro and their proteoglycans compared to those isolated from lung tissue. From these studies an in vitro system will be chosen which most resembles the in vivo connective tissue biosynthetic system.